Deployable beam structures are required for many applications aboard the proposed space station as well as uses in other free flying satellites. These structures must package efficiently for launch into orbit and deploy reliably upon command. A number of deployable beam concepts have been proposed and compared. (see Greenberg, H. S.: Development of Deployable Structures for Large Space Platforms. NASA CR-170689, December 1982, and Cox, R. G. and Nelson, R. A.: Development of Deployable Structures for Large Space Platforms. NASA CR-176090, December 1982.) Most of these proposed concepts require sophisticated mechanisms to deploy the beam or platform in space. The deployer system for these structures may have a mass that exceeds the mass of the structure, and after the structure is deployed the deployer serves no useful function. Deployable structures also frequently have special joints and hinge mechanisms that are required to insure deployment, and many of these mechanisms are complicated because they must lock in place when the structure, or portions thereof, is fully deployed. To reduce the joint complexity, many of these concepts are single-fold configurations in that the structure only folds in planar sections. While this reduces complexity, it also increases the stored volume, thus reducing the packaging efficiency. The combined effects of the deployment mechanisms, joint complexity and packaging efficiency frequently compromises the deployment reliability and the structural performance to such an extent that the deployable structure may be unsuitable for many applications. The mechanical complexity of the deployer also makes the system very costly to design and develop.
Other foldable structures, of which there is a great abundance, were not designed with the requirements of space application in mind. Structures used for folding tents or shelters on earth are generally inappropriate for use in space, due to inadequate packaging and deployment methods. Existing earthbound structures were not designed to make up structural beams 400 feet in length, as might be required for the construction of a space station.
It is therefore an object of the present invention to provide a foldable beam and/or planar truss structure suitable for space application which is synchronously deployable.
It is a further object of the present invention to provide a synchronously deployable structure which operates without the use of a complicated deployment mechanism.
Another object of the present invention is to provide a synchronously deployable structure which utilizes simple, single degree-of-freedom connection points.
Another object of the present invention is to provide a space structure which collapses into an efficient and dense configuration for transportation in the Space Shuttle cargo bay.